In general, a vehicle employing an electric motor as a power source emits small noise when being ready to travel or when traveling. Therefore, people outside or inside the vehicle can hardly notice the vehicle being ready to travel and can hardly notice the vehicle being traveling. In consideration of this, a proposed device is configured to emit a specific sound to notify people of a vehicle being ready to travel or being traveling.
For example, JP-A-2005-343360 discloses a vehicular device configured to emit a predetermined alarm sound when the vehicle travels with an electric motor. The device of JP-A-2005-343360 employs a microcomputer to generate the alarm sound. The microcomputer is equipped with a memory device storing date related to the alarm sound. In the conventional configuration of JP-A-2005-343360, the microcomputer needs a storage area to store sound source data related to the alarm sound. In addition, a considerable processing load is applied to the microcomputer in order to generate the alarm sound at a high frequency of several kilohertz. Therefore, an exclusive electronic control unit is conventionally requisite to generate an alarm sound with a microcomputer. Alternatively, it is conceivable to employ an existing vehicular electronic control unit with an additional function to generate an operation notification sound. Nevertheless, in this configuration, the existing vehicular electronic control unit needs to be equipped with a high-performance microcomputer. Thus, in a conventional configuration, a large-scale device and/or a large number of additional circuit components are requisite to generate an operation notification sound.